It is said that an era of “Internet of things (IoT)” including a trillion pieces of equipment (nodes) is coming. In order for this network to run normally, the equipment needs to be connected correctly, to operate normally, and to be maintained properly. To that end, means for identifying individual nodes connected to the network distinctly and easily is required. This gives rise to the need to assign each individual node a unique ID (an index for identification) that makes copying and impersonation difficult. The assigning of an ID is indispensable particularly to identify individual pieces of equipment and apparatus having exactly the same performance as a result of giving importance to uniformity, which allows the equipment and apparatus to be mass-produced inexpensively.
In the Internet, IP addresses are used as IDs to discriminate pieces of equipment connected to this network from one another. A method used to distribute IP addresses has initially been IPv4, but is now being shifted to IPv6 as the rapid increase in the number of pieces of equipment connected is depleting available IPv4 numbers.
A unique MAC address is assigned to each piece of equipment connected to a network in order to manage the piece of equipment. The MAC address is one of bases of a UUID, which is a standard provided in order to prevent duplication on a network. Other than simply assigning an ID number, there are cases in which an ID suitable for a situation is set. An example of such cases is “ucode”, which is a standard promoted by the Ubiquitous ID Center.
Next, it is necessary to confirm that information (an electronic document or the like) received from equipment connected to a network has not been, for example, falsified or tampered (authentication of information). Data recorded in a storage apparatus of a network or of information communication equipment, in particular, is digital data and cannot be distinguished as the original from data that is a copy of the recorded data (cannot be proved as original data autonomously in an apparatus used to create the recorded data). For example, a method of checking digital data through public key cryptosystem electronic signature by providing an outside certificate authority is used to prove that the digital data is original data (see Patent Literature 1, for example). In electronic signature handled by the certificate authority, the hash value of data is obtained by a signee and encrypted with a private key, and the encrypted hash value is issued along with the document. The receiver calculates the hash value of the data, and compares the calculated hash value to a hash value decrypted with a public key to check the data.
Time stamp authentication is used as a system for proving the time at which digital data is generated (when digital data is generated). The reliability of a built-in clock is generally low in pieces of information communication equipment connected to a network. The pieces of information communication equipment therefore receive a time stamp authentication token issued by a time stamp authority (TSA) that uses a time authority (TA), create the hash value of the token and the hash value of digital data, and rely on the outside time stamp authority again by having the time stamp authority check the hash values.